Even though large areas of the US are experiencing extreme drought conditions, aggressive summer thunderstorms have also swept across parts of the nation – and according to a team of scientists at Harvard University, those storms may be damaging the ozone layer. The Harvard scientists believe that rising levels of carbon dioxide and methane may be increasing the severity of these storms, and they may have found the first significant connection between climate change and ozone layer destruction.

The report was published in Science, in which Harvard Professor of Atmospheric Chemistry James G. Anderson explained his discovery of serious—and wholly unexpected—ozone loss during the summer. Previously, it was thought that the complex atmospheric chemistry known to destroy the ozone only occurred at very cold temperatures, such as over polar regions. However the Harvard team have discovered that during intense summer storms, water vapor is thrust by convection far higher into the lower stratosphere than previously thought possible. This alters the atmospheric conditions in a way that “leads to substantial, widespread ozone loss throughout the ensuing week.”

And of, course, the ozone layer is pretty important—it stops the sun’s ultraviolet light from reaching the earth and protects against the damaging radiation that can cause skin cancer. It was previously thought that the ozone layer was particularly susceptible to chemicals of man-made origin, such as chlorine and bromine and that previous damage was a result of the widespread commercial use of CFCs.

In their study however, the Harvard found that the loss of ozone over populated mid-latitude regions in summer was linked directly to the frequency and intensity of big storms. What is worse, is that these storms are going to be getting larger thanks to the rising levels of carbon dioxide and methane in the atmosphere.

“We were investigating the behavior of convective water vapor as part of our climate research,” Anderson says, “not ozone photochemistry. What proved surprising was the remarkable altitude to which water vapor was being lofted—altitudes exceeding 60,000 feet—and how frequently it was happening.”